Karl Popper's Conclusions About Good Theories

It is easy to obtain confirmations, or verifications, for nearly every theory — if we look for confirmations.     Confirmations should count only if they are the result of risky predictions; that is to say, if, unenlightened by the theory in question, we should have expected an event which was incompatible with the theory — an event which would have refuted the theory.     Every "good" scientific theory is a prohibition: it forbids certain things to happen. The more a theory forb...

 The Difference Between Science and Pseudoscience

What I had in mind was that his previous observations may not have been much sounder than this new one; that each in its turn had been interpreted in the light of "previous experience," and at the same time counted as additional confirmation. What, I asked myself, did it confirm? No more than that a case could be interpreted in the light of a theory. But this meant very little, I reflected, since every conceivable case could be interpreted in the light Adler's theory, or equally of Freud's. I...